This invention relates to apparatus for folding spaced segments of web material and, more particularly, to apparatus for the production of disposable articles which embody folding a side flap inwardly.
Folding of an article such that two outer panels are folded inwardly and are superposed on the top or bottom of a central panel is a well-known practice, but it is limited to longitudinal folds where folding of the side margins is made while the continuous web is moving.
For special disposable products, for example, an incontinent pad or garment similar to the disposable article in U.S. Pat. No. 4,500,316, it is desirable to have a discreet marginal portion of "flap" overfolded from both sides to add significantly to the absorption capacity of the central "crotch" portion. Folding of the side panels which are severed approximately 1/3 of the web width from a marginal edge cannot be accomplished continuously or by means of conventional folding boards because the web is no longer continuous but is cut into predetermined segmented side flaps or panels which must be folded individually.
For the incontinent pad of '316, the flap portion on each side is folded toward the center and is superposed on the central absorption pad, thus increasing its thickness and absorption capacity approximately three times, and this desirable folding enhances the function and utility of said pad.
In order to fold discrete segments or side flaps, a phased device must be used to fold the side flap inwardly from each side, but prior art does not teach how discreet web portions can be folded inwardly while moving, nor does it teach mechanical elements which can grip and transfer said flaps. Additionally, there are no prior art teachings which relate to control of the central pad portion while the side folds are being made. The inventive device, therefore, teaches "C" folding of side web segments (flaps) toward the central portion of an absorbent pad and the like while the central portion is held and controlled to prevent transverse movement.
While the inventive device is particularly useful to selectively fold side portions of the web as defined in Patent '316, the method and device can be useful to complete an overlapped "C" fold for other disposable products made from a web which is partially continuous and partially severed on one or both sides in a repeating fashion to form flaps.
According to the invention, a vacuumized continuously moving belt means selectively grips one surface of the continuous web while a frictionalized continuously moving belt system engages the opposite surface of the web, the frictionalized belt system being arranged at an angle to the path of movement of the web to progressively fold flap portions while the web material is advancing in the path.
Other objects and advantages of the invention may be seen in the details set forth in the ensuing specification.